The present invention relates to Air Cycle Machines (ACMs). ACMs may be used to compress air in a compressor section. The compressed air is discharged to a downstream heat exchanger and further routed to a turbine. The turbine extracts energy from the expanded air to drive the compressor. The air output from the turbine may be utilized as an air supply for a vehicle, such as the cabin of an aircraft. ACMs may be used to achieve a desired pressure, temperature, and humidity in the air that is transferred to the environmental control system of the aircraft.
ACMs often have a three-wheel or four-wheel configuration. In a three-wheel ACM, a turbine drives both a compressor and a fan which rotate on a common shaft. In a four-wheel ACM, two turbine sections drive a compressor and a fan on a common shaft.
Airflow must be directed into the fan section to the compressor section, away from the compressor section towards the heat exchanger, from the heat exchanger to the turbine or turbines, and from the final turbine stage out of the ACM. In at least some of these transfers, it is desirable to direct air radially with respect to the central axis of the ACM. To accomplish this, rotating nozzles may be used to generate radial in-flow and/or out-flow.
ACMs often have more than one housing section. The housings used in an ACM are used to contain airflow routed through the ACM, as well as rotating parts. Often, housing components are configured adjacent to seals and/or other housing components to achieve airflow containment.